Means and method for preparing and introducing fuel charges into internal-combustionengines



' 1,527,261 F. MADLER MEANS AND METHOD FOR PREPARING AND INTRODUCING FUELI CHARGES Feb. 24, 1925.

INTO INTERNAL COMBUSTION ENGINES Filed April 26, 1922 [nwmfar lmm/ifa'kiler 6? ML 1 14 I Patented Feb. 24, 1925.

UNITED STATES PATENT OFFICE.

FRANZ MADLER, 0F BERLIN, GERMANY, ASSIGNOR T0 MAEDLER ENGINE CORPORA- TION, A CORPORATION OF MARYLAND.

MEANS AND METHOD FOR PREPARING AND INTRODUCING FUEL CHARGES INTO IN- TERNAL-COMBUSTION ENGINES.

Application filed April 26, 1922.

To all whom it may concern: Be it known that I, FRANZ MKDLER, a citizen of Germany, residing at -21 Emserstrasse, Berlin lV., Germany, have invented certain new and useful Improvements in Means and Methods for Preparing and Introducing Fuel Charges into Internal-Combustion Engines, of which the following is a specification.

This invention is for means and methods for preparing and introducing predetermined fuel charges into the working cylinders of internal combustion engines.

If a spray carburettor is arranged in the suction pipe of an internal combustion engine, the character of the combustible mixture formed is affected to a very great ex:-

tent by the speed of the engine and by the density of the air. It is also necessary to make special arrangements so that'the extremely rich mixture which has to be produced in order to start the engine easily and enable it to operate at low speeds can be diluted as the engine speed increases. The adaptation of the fuel supply to the air pressure requires further" special provision. Even if the necessary quantity of fuel is introduced by means of a fuel pump, the regulation of the small quantities of fuel needed at certain times involves considerable constructional difliculties.

The object of this invention is to provide means for and methods of preparing, regulating and introducing the necessary fuel charge at a practically constant velocity into the air charge in the working cylinder regardless of the speed and load of the engine.

This is accomplished by utilizing a predetermined vacuum in an auxiliary cylinder to draw in a fixed volume of a gaseous medium irrespective of engine speed and load. This gaseous medium, or a portion thereof, carries with it a predetermined fuel charge into the auxiliary cylinder, where the mixture is compressed and then injected into a less highly compressed air charge in the Working cylinder.

The auxlliary cylinder is constructed in the form of a pump, so designed that there will always be a constant volume of gaseous medium plus fuel. charge sucked into the pump at the end of each vacuum stroke of the pump piston. The construction and op- Serial No. 556,746.

eration of the fuel pump are such that the interior or pump chamber is absolutely cut pump chamber regardless of engine speed.

The fuel, as it is carried into the pump by the high velocity of the gaseous medium, becomes finely distributed throughout the pump chamber. Upon compression of the mixture, the heat of thegaseous medium (caused by the compression) acts upon the finely distributed particles of fuel to complete their atomization and mixing with ithe gaseous medium to produce a homogeneous gaseous fuel charge, which is readily combustible. At the end of the compression stroke of the pump piston, the pump chamher is placed in communication with the less highly compressed '-air charge in the Working cylinder, and the prepared fuel charge is automatically injected into the air charge at constant velocity independent of engine speed or load.

The fuel-supply device of the fuel pump, from which the gaseous medium extracts a fuel charge, comprises a fuel nozzle or jet arranged in a passage through which the gaseous medium flows on its Way to the pump. medium entering the evacuated pump cham ber is'constant, the velocity of the gaseous medium past the fuel jet can be regulated to vary the amount of fuel sucked out of the nozzle and carried into the pump.

The invention will be more fully described in connection with the illustrative embodiment shown in the accompanying drawing, in which Fig. 1 is a lon itudinal section through the main and auxiliary cylinders of a twocycle engine according to the invention.

Fig. 2 is a partial cross section showing a possible arrangement of channels that. con nect the auxiliary and main cylinders, and

Fig. 3 shows a valve arrangement of the While the velocity of the gaseous.

auxiliary cylinder which is employed in engines arranged for self-ignition of the fuel charge or where it is desirous to obtain the best possible practical vacuum.

In Fig. 1, a main or operating cylinder 1 is shown provided with the main piston 3, an air inlet ort l3 controlled by a valve 14, and an exhaust port 15.; Connected with the main cylinder 1 is an auxiliary' pylinder 2 in which reciprocates a piston 4 connected to a rod 16. The'valve 14 and rod 16'are operated from the cam-shaft of the engine by any suitable arrangement, as will be understood, for timing their movements with those of the working piston 3. In the particular instance illustrated, the auxiliary piston 4 has an annular groove 5 arranged to register with orts or channels'6 and 7 when the piston is at the top of its stroke. The annular groove 5 communicates with the compression chamber 2' in the auxiliary cylinder 2 by means of a longitudinal bore 9 and a transverse bore or passage 8 in the auxiliary piston. In Fig. 1, the parts 11 and 17 represent more or less diagrammatically a fuel-supply device in which 11 is an air passage sleeve and 17 a fuel nozzle extending from a source of fuel supply into the air passage. Attention is called to the fact that the parts 11 and 17 do not constitute a carburetor in the accepted meaning of that term. A carburetor is a devicefor forming an explosive mixture 'of h drocarbon fuel and air. In the fuel-supp y device repre- .sented by the parts 11 and 17, the atmospheric air or-other gaseous medium drawn through the passage 11 acts as a carrier of a predetermined quantity of fuel from the nozzle 17 into the auxiliary cylinder, as

presently explained. I A ipe 18 connects the fuel-supply device wit an annular recess or chamber 19 formed in the auxiliary cylinder2. A series of ports 10. connect the c amber 19 with the interior of the auxilia cylinder.

e operation of the apparatus abovede scribed is as follows:

Du; 'ng the outward movement of pump piston 4, a predetermined. vacuum is created in the pum chamber independently of the speed. at w ich the pump piston operates. When .the' annular groove 5 registers with ports 10, the vacuum in the pump chamber causes a constant ume of agaseous me- I the passage 11 of the pp] device and'carry m h it a predeterm ne quantity of fuel from the nozzle 17 through ports 10, annular roove 5, channels8 and 9, and thence intot e space above t iqauxiliary iston. Tlhis mixture of fuel andf-"air thus rawn'into .the auxiliary cylinder .is excessively richand is non-combustible or nonregplliosive (I use the terms synonymously); eh I speak of this mix ture as non-combustible, I mean that it does in its innermost position, communication is established between the compression space 2 in the pump and the interior of the working cylinder. It' will be understood, of course, that an air charge has previously been admitted into the working cylinder by the properly timed valve 14 through the air port 13. The moment when the annular groove 5 registers with channels 6 and 7, the highl stantly in ected under its own ressure into the less highly compressed air 0 arge in the working cylinder, where the fuel charge mixes with the air charge to produce the combustible or explosivemixture for the engine. I

The relative movements of working iston 3 and pump piston 4 are sotimed t lat, at the moment of fuel injection, the air charge in the working cylinder is under lower compression than the fuel charge in the auxiliary cylinder. In the illustrative embodiment shown in Fig. 1, the fuel' injection occurs when the air charge in the working cylinder has just been enclosed and compressed fuel. charge is inis therefore at approximately atmospheric cylinder is out off, and the .pump chamber remains absolutely cut off from all sources of communication, so that the outward pie-- ton stroke creates a constant vacuum re- Inn of the speed at which thesplston operates.

The passages 5,8 and 9, with piston 4, constitute a convenient. form of valve for establishing and cuttin ofl' communication between the interior 0 the pump chamber the working cylinder at the proper int'ervals. In the broader aspect of m invention, any practical construction an. design of valve or valves may beemployed for controlling communication between the working cylinder and the fuel-compression chamber. As the passages 5, 8 and 9 are comparatively small, the, minute quantity of gaseous medium that may remain therein after fuel injection does not interfere with the constant vacuum produced by the outward stioke of the pump piston. -Whatever other form of controlling valve may be used, it should leave as little clearance space as possible for residual gases in the pump chamber after injection of the fuel.

It oes without saying that during 'the -peri in which the pump piston 4 recipro cates, as described, the compression, .igni

tion, expansion, exhaust and charging operations take place in the working cylinder, and a new cycle of operations then commences. This will be understood without further description.

- The air or other gaseous medium that rushes into the auxiliary cylinder 2 performs the two-fold function of carrying a predetermined quantity of fuel into the pump chamber and, upon compression, preparing the fuel-charge in a finely divided state throughout the gaseous medium. As a result, the hot and highly compressed fuel charge enters the working cylinder in a condition of practically complete volatilization and instantly produces with the air charge a readily combustible or explosive mixture.

The openings orports 10 are preferably made square and placed so that two sides of each port lie horizontal. By this construction and arrangement of the ports 10 the freest possible connection is, instantly established between the. auxiliary cylinder and the atmosphere or other gaseous medium, thus producing a rapid inrush of air and fuel into the vacuum of the auxiliary cylinder.

The inflow-passages ,through whlch the compressed mixture passes from the auxiliary cylinder into the main cylinder maybe (but need not be) disposed so as to give rise to a number of intersecting jetsin the main cylinder. An arrangement ofthis kind is shown in Fig, 2 as a possible construction, which, however, is not material to my invention.

The engine is regulated for various speeds and loads, 1 (by altering the sectional area of the air passage at the fuel outlet or 2) by changing the sectional area of. the fuel emit tin nozzle. In either case the quantit of fue entrained or carried by the flow 0 air or. other gaseous medium past the fuel nozzle 17 into the auxiliary cylinder 2 is regulated in proportion to the speed or load of the engine. The said adjustments may be obtained for example by raising or lowering the sleeve 11. v

The novel process is also applicable to four cycle engines in which the auxiliary piston would execute one half the number of strokes performed by the mam (piston. The time of mjection of the prepare fuel charge into the main cylinder can be regulated in a similar manner as in two-stroke engines, previously described.

and the main cylinder, and betweenthe main cylinder and the fuel-supply device may be controlledby valves instead of by means of passages in an auxiliary piston as shown.

The degree of compression of the excessively rich mixture in the auxiliary cylin- (161 is such that the heat developed bythe compression of the gaseous medium so acts upon the intermixed fuel that the same becomes finely and homogeneously distributed throughout the gaseous medium. I have demonstrated that the finely distributed fuel in the auxiliary cylinder absorbs heat from the compressed gaseous medium and this prevents the fuel from being broken .up when subjected to this high temperature and pressure. The gaseous medium and fuel must be so proportioned that the atomized fuel becomes homogeneously distributed throughout the gaseous medium and, therefore, 1s in an ideal form for injection and combustion. At the same time, this inter:- change of heat prevents the fuel from being broken up under the high temperature that the compression of the gaseous medium would normally produce.-

The novel process can, however,alsq be applied to self-ignition engines. In a twocycle en 'ne the two pistons would then be arrange to approximately keep pace with each other as regards direction and speed of stroke. The charge in the auxiliary cylinder is compressed sufficiently to cause it to ignite: But only as much fuel will be burnt as will be permitted by the amount of air contained in the auxiliary cylinder. The rest is blown into the highly compressed air charge of the main cylinder by the more highly compressed gases in the auxiliary The communication between the auxiliary ion cylinder when the two pistons-are in their top dead center positions. Highly-com-' pressed gases of'combustion remain in the auxiliary cylinder. During thedownward travel of the auxiliary piston a valve 12 (Fig. 3) associated with the auxiliary cylinder is momentarily o ened by suitable positively acting controlling gear, the communication between the two cylinders being previously cut off. The pressure in the auxiliary cylinder is reduced to that of the atmosphere by the opening of the-valve 12 and this ressure is. reduced still further and a pre etermined vacuum is formed im 'mediately before the annular groove reaches the bottom inlet ports. In all other respects the mode of operation is the same as that hereinbefore described.

' It can be easily understood that the valve" 12 shown in Fig. 3 may be used in lieu of passages 6, 7, 8 and 9 (see Figs. 1 and '2) to control theadmiss'ion of the highly com pressed non-explosive fuel charge into the less highly compressed air charge into the tann n th working cylinder at the time when the auxiliary piston 4: is at the top of its compression stroke. In that case, the valve 12'is arranged to operate in such a manner that it closes the moment when the auxiliary pist n 4 starts to move on its vacuum stroke.

it will 'be clear from the foregoing that I have provided a very simple and efiicient method and means for uniformly regulating'the fuel charge of a combustion engine without the use of a carburetor, regardless of the speed of the engine. As may be seen from the drawings, the auxiliary cylinder is quite small in comparison with the working cylinder, so that but little ower is reguired to operate the auxiliary piston.

ince the auxiliary piston creates a predetermined vacuum, it is evident that the quantity or volume of gaseous medium drawn into the auxiliary cylinder is practically the same at all times, irrespective of engine speeds and atmospheric conditions, and this volume of gaseous medium carries with it the same amount of fuel for a given adjustment of the fuel-supply device. (Jonsequently, the degree of compression of the fuel charge in the auxiliary cylinder is always the same. Since the air charge in the working cylinder is at a lower pressure than the compressed fuel charge when the latter is blown in from the auxiliary cylinder, this rushing in of therich fuel tends to produce a finely divided and uniformly distributed explosive and (or) combustible mixture. claim:

1. A method of preparing and Introducing fuel charges into the working cylinder of an internal combustion engine, wh ch comprises filling the working cylinder with an air charge, creating a predetermined vacuum in a, closed chamber independent of the engine speed or load, utilizing said vacuum to draw into the evacuated chamber a fixed volume of a gaseousmedi'um which carries with it a predetermined quantity of fuel. into said chamber, said fuel and gas-y eousj. medium forming a rich non-explosive mixture in said chamber, compressing said p o i eu cha ge n aid cha r d th re? cau he f el t b ome n l dis r but hro ghout as: g ou medium. and nject ng th oin r s teal shares i o the a l 'i halr nt ,ewar i a 'lied at a when s en et v l ci in. send ant 9f n ne 5 d th inje d feel cha air thar fi cemh stible mi ure for th engine-1" A m hed'af prep rin e u a n int'l 'od in ee h'fli esiil e new" cylinder of an internal combustion engine,

a which mp is s fi lin the wrkin t l n r i an r a e 'c'rent'in "wease ra d uum in bsd emb r' ind pendent of the engine or load, utilizmg said vacuum to draw into'the evacuated a as msliumfo min e chamber a-fixed volume of a gaseous medium which carries with it a predetermined quantity of fuel into said chamber, said fuel and gaseous medium forming a rich nonexplosive mixture into said chamber, regulatlng the quantity of fuel which is carried into the auxiliary chamber by the fixed volume of gaseous medium drawn in by the vacuum, compressing said non-explosive fuel charge in said chamber and thereby causing the fuel to become finely distributed throughout the gaseous medium, and injecting this compressed fuel charge into the air charge in the working cylinder at a practical y constant velocity independent of engine speed, the injected fuel charge forming with the air charge the combustible mixture for the engine.

3. In a method of preparing and introducing fuel charges into an air charge in the working cylinder of an internal combustion engine, the steps which.c0nsist in creating a predetermined vacuum vin a closed chamber independent of the engine speed or load, andthen connecting this evacuated chamber simultaneously with a gaseous medium and with a source of fuel supply, whereby a fixed volume of gaseous medium is sucked by the vacuum 1I1l30, said chamber and carries with 1t a predetermined quantity of fuel from sald source of fuel supply, this fuel and gaseous medium forming a rich non-explosive mlxture, compressing said non-explosive mixture of fuel and gaseous medium, and connecting the chamber with the working cylinder to in 'ect the highly compressed fuel charge into t e less highly compressed air charge in the working cylinder at practically constant velocity independent of engine speed.

4. In internal combustion engines, as a means for controlling and preparing a fuel charge for in'ection into an air charge in the main cylinder, an auxiliary chamber arranged tobe connected with the main c linder at predeterminedintervals, means br creating a redetermined vacuum in said chamber in ependent of eugine speed or load, a fueLsupplying device so constructed tha a g s ou medi m pas ng her feugh carri s w th it a pr d termined qua y f tea i aid. hamber; a d means f ra tomatictl y bomiecting d ie i ed chm her with. ai feelisurp y' n de i e, hereby afi ed vqlu ne'ofsa us medium. I 'r ying w aera e mime into the ev i ate. "spa e n aid a'fill the same, an fuel and gasri h nenrexp osiv mixture adapted to be compressed and inieeted in the e i ly omp se a char 'e in the'i'nain cylinder to form a com.- bustfifle mixture with said aircharge, 5.111 internal combustion engines, as a means for controlling and preparing a fuel charge for injection into the air charge in the main cylinder, an auxiliary chamber arranged to be connected with the main cylinder at predetermined intervals, means for creating a predetermined vacuum in said chamber independent of engine speed or load, a fuel-supplying device so constructed that a gaseous medium passing therethrough carries with it a predetermined quantity of fuel into said chamber, means for automatically connecting said evacuated chamber with said fuel-supplying device, whereby a fixed volume of gaseous medium carrying with it a predetermined quantity of fuel is sucked into the evacuated space in said chamber to fill the same, said fuel and gaseous medium forming a rich non-explosive mixture adapted to be compressed and injected into the less highly compressed air charge in the main cylinder to form a combustible mixture with said air charge, and means in said fuel-supplying device for regulating the quantity of fuel carried into said chamber by the fixed volume of gaseous medium.

6. In an internal combustion engine, a working cylinder adapted to receive and compress an air charge, an auxiliary chamber, means for creating a predetermined vacuum in said chamber independent of engine speed or load, connections for causing said vacuum to draw in a fixed volume of a gaseous medium which carries with it a predetermined quantity of fuel into said chamber, means for compressing the mixture of fuel and gaseous medium in said chamber to a predetermined degree, and means for injecting said'compressed mixture into the less highly compressed air charge in the working cylinder at a practically constant velocity independent of engine speed.

7 In an internal combustion engine, a main cylinder having a port for the admission of air, a working piston in said main cylinder, an auxiliary cylinder adapted to be connected with the main cylinder, a pis ton in said auxiliary cylinder adapted to create a predetermined vacuum therein in one stroke while the auxiliary cylinder is closed and to create a compression on the other stroke, a source of fuel-supply having means for permitting a flow of gaseous medium to carry with it a predetermined quantity of fuel, connections foriopeniirg" communication between said fuel supply and said auxiliary cylinder when the auxiliary piston has completed the vacuum stroke, whereby a fixed volume of gaseous medium carrying with it a predetermined quantity of el is drawn into the auxiliary cylinder to til the previously evacuated space therein, the compression stroke of the auxiliary piston"oompressing the non-explosive fuel char e in the auxiliary cylinder. and means for injecting the compressed fuel charge into the air charge of the main cylinder at practically constant velocity independent of engine speed, the injected fuel charge form ing a combustible mixture with said air charge. A

8. In an internal combustion engine, a main cylinder having a port for the admission of air, a working piston in said main cylinder, an auxiliary cylinder adapted to be connected with the main cylinder, a piston in said auxiliary cylinder adapted to create a predetermined vacuum therein on one stroke while the auxiliary cylinder is closed and to create a compression on the other stroke, a source of fuel supply having means for permitting a flow of a gaseous medium to carry with it a predetermined quantity of fuel, means for regulating the quantity of fuel carried by a fixed volume of gaseous medium into the evacuated auxiliary cylinder, connections for opening communication between said fuel supply and said auxiliary cylinder when the auxiliary piston has completed the vacuum stroke, whereby a fixed volume of gaseous medium carrying with it a predetermined quantity of fuel is drawn into the auxiliary cylinder to fill the previously evacuated space therein, the compression stroke of the auxiliary piston compressing the fuel charge of the auxiliary cylinder, and means for injecting the compressed fuel charge into the air charge of the main cylinder at practically constant velocity independent of engine speed, the injected fuel charge forming a combustible mixture with said air charge.

9. In an internal combustion engine, a main cylinder having a port for the admission of air, a working piston in said. main cylinder, an auxiliary cylinder adapted to be connected with the main cylinder and provided with an annular chamber having a series of ports, a piston in said auxiliary cylinder adapted to create a predetermined vacuum therein on one stroke while the auxiliary cylinder is closed and to create a compression on the other stroke, said auxiliary piston being provided with a circumferential groove and with an axial bore communicating with said groove and extending to one end of the piston, said groove being arranged to register with said ports in the annular chamber at the end of the vacuum stroke of the auxiliary piston, a source of fuel supply having means for permitting a flow of a gaseous medium to carry withit a predetermined quantity of fuel, a connection between said fuel supply and said "annular chamber, whereby the auxiliary cylinder is connected with the fuel supply passage when the circumferential groove in the auxiliarypiston registers with the ports in said annular chamber, said ports being so constructed and arranged that full and free communication is almost instantly established between the auxiliary cylinder and a gaseous medium, whereby a fixed volume of gaseous medium carrying with it a predetermined quantity of fuel is drawn into the auxiliary cylinder to fill the previously evacuated space therein, the compression stroke of the auxiliary piston compressing the fuel charge in the auxiliary cylinder, and means for injecting the compressed fuel charge into the air charge of the main cylinder.

10. A method of preparing and introducing fuel charges into the working cylinder of an internal combustion engine, which comprises filling the working cylinder with an air charge, creating a predetermined vacuum in a closed chamber independent of engine speed or load, utilizing said vacuum to draw into the evacuated chamber a fixed volume of a gaseous medium, causing said gaseous medium to draw a predetermi1i'ed amount of fuel from a source of fuel supply and to carry the metered fuel into the evacuated chamber. said fuel and gaseous medium forming a rich non-explosive mixture in said chamber, compressing said nonexplosive fuel charge in said chamber and thereby causing the fuel to become finely distributed throughout the gaseous medium, and injecting the compressed fuel char e into the air charge in the Working cylinder at a practically constant velocity independent of. engine speed, the injected fuel charge forming with the air charge the combustible'mixture for the engine.

a 11. method of preparing, regulating and introducing fuel charges into the working cylinder of an internal combustionengine, which comprises filling the working cylinder with an air charge, creating a predetermined vacuum in a closed chamber independent of engine speed or load, utilizing said vacuum to draw into the evacuated chamber a fixed volume of a gaseous medium, causing the gaseous medium to draw a predetermined amount of fuel from a source of fuel supply and to carry the metered fuel into the evacuated chamber,

causing the gaseous medium to control the quantity offuel whleh it draws from thesource of fuel supply and carries intothe evacuated chamber, compressing said non explosive fuel charge in said chamber and thereby causing the fuel to become finely distributed throughout the gaseous medium, and injecting the compressed fuel charge into the air charge in the working cylinder at a practically constant velocity independent of engine speed, the injected fuel forming with the air-charge a combustible mixture for the engine.

12. In internal combustion engines, as a means for controlling and preparing a fuel charge for injection into an air charge in the main cylinder, an auxiliary chamber ar;

ranged to be connected with the main cylinder at predetermined intervals, means for creating a predetermined vacuum in said chamber independent of engine speed or load, a fuel-supplying device so constructed that a. gaseous medium passing therethrough carries with; it a predetermined quantity of fuel into said chamber, means for automatically connecting said evacuated chamber with said fuel-supplying device, whereby a fixed volume of gaseous medium carrying with it ,a predetermined quantity of fuel is sucked into the evacuated space in said chamber to fill the same, said fuel and gaseous medium forming a rich non-explosive mixture adapted to be compressed and injected into the less highly compressed air charge in the main cylinder to form a combustible mixture with said air charge, and means for causing the gaseous medium to control the quantity of fuel carried into said chamber by the fixed volume of gaseous medium. a

13. A method of preparing a metered amount of hydrocarbon fuel for combustion in a separate air charge, which com- .prises filling a cylinder With a constant volume of a mixture consisting of a hydrocarbon fuel in the form of a spray and a gaseous medium, such gaseous medium consisting of gas incapable of supporting combustion or containing oxygen in such small proportion that the resultant mixture is practically non-inflammable until released into a separate air charge, and subjecting said fuel mixture to the action of high com pression until the heat developed by the compression of the gaseous medium so acts upon the hydrocarbon fuel that the same becomes finely and homogeneously distributed throughout the gaseous medium, said mixture remaining practically non-inflammable even under said high compression, said intermixture of gaseous medium and hydrocarbon fuel being so proportioned that the heat to which the mixture is subjected by such compression will not cause the hydro carbon fuel to char or become disintegrated.

14. A method of preparing a metered amount of'hydrocarbon fuel for combustion in a separate air charge, which comprises creating a predetermined vacuum in a cyllnder, causing said vacuum to draw into the cylinder aconstant volume of a controllable mixture of a gaseous medium and a hydrocarbon fuel in the form of a spray, said gaseous medium consisting of gas incapable of supporting combustion or containing oxy en in such small proportion that the resu tant mixture is ractically non-inflammable until released into a separate air charge, and subjecting said fuel mixture to the action of high compression until the heat developed by the compression of the gaseous medium so acts upon the hydroacts upon the hydrocar comprises an auxiliary cylinder, means for filling said auxiliary cylinder with a constant volume of a non-combustible mixture consisting of a gaseous medium and a hydrocarbon fuel in the form of a spray, and'a. piston operable in said cylinder for raising the temperature of said mixture by compression only until the heat developed by this compression of said aseous medium so 11 fuel that the same'becomes finely and homogeneously distributed throughout the gaseous medium, said mixture remaining practically non-inflammable even under said compression, said ,intermixture of gaseous medium and hydrocarbon fuel being so proportioned that the heat to which the mixture is subjected by said compressionwill not cause the hydrocarbon fuel to char or become disintegrated.

16. Apparatus for preparing av metered charge of hydrocarbon fuel for combustion in an air charge in the working cylinder of an internal combustion engine, which comprises an auxiliary cylinder, a piston in said auxiliary cylinder .for alternately creating a predetermined vacuum and compression therein, and means for causing said vacuum to draw into the auxiliary cylinder a fixed volume of a controllable non-explosive mixture consisting of a. gaseous medium and a hydrocarbon fuel in the form of a spray,

said piston on its compression stroke sub-- jecting said mixture to the action of hi h compression until the heat developed by t e compression of the gaseous medium'sa acts upon the hydrocarbon fuel that the same becomes finely and homogeneously distributed sion of air and an exhaust port, a working piston in said main cylinder, an auxiliary cylinder adapted to be connected with the main cylinder and provided with an annular chamber having a series of ports, a piston inside. said auxiliary cylinder adapted to create a predetermined vacuum therein on one stroke while the auxiliary cylinder is closed and to create a compression on the other stroke, said auxiliary piston being arranged to uncover said ports in the annular chamber at the end of the vacuum stroke, a source of fuel-supply having means for permitting a How of a gaseous medium to carry with it a predetermined quantity of fuel, a connection between said source of fuel-supply and said annular chamber whereby the auxiliary cylinder is connected with the fuel-supply passage when the auxiliary piston uncovers the ports of said annular chamber, said ports being so arran ed that full and free communication is a 0st instantly established between the auxiliary cylinder and a gaseous medium, whereby a fixed volume of gaseous medium carrying with it a predetermined quantity of fuel is drawn into the auxiliary cylinder to fill the previously evacuated space therein, the compression stroke of the auxiliary piston compressing the fuel charge in the auxiliary cylinder, and means for injectingthe compressed fuel charge into the less highly compressed air charge inthe main cylinder.

In testimony whereof I have signed this specification in the presence of two witnesses. N

- FRANZ MADLER. Witnesses:

Arno Bo'rno, -E. HOLTZERMAN. 

